THE EFFECT OF MOVEMENT ON CAMOUFLAGE USING JUMPING SPIDERS AS MODEL PREDATORS

Abstract

Motion has long been believed to “break” camouflage, as abrupt movements can be easily detected even before the animal is recognized. However, recent studies have shown otherwise, albeit still limited. Here, I explored if there were differences in detectability of computer-generated stimuli (i.e. conspicuous and background matching) moving at varying speeds across six jumping spider species. I also tested if blurring of high-contrast patterns (i.e. flicker fusion camouflage) can occur at high speeds using Menemerus bivittatus and masked their antero-median or antero-lateral eyes. Results indicated differences in motion detectability among species, thus suggesting differences in visual acuity within the same subfamily. Salticid responses were significantly lower for background matching stimuli. Blurring of high-contrast patterns were also observed to occur at high speeds, depending on the masking treatment. Taken together, I show that background matching and flicker fusion camouflage are effective in reducing detectability of moving stimuli.